Features

Complete list of implemented and planned features in MentOS.

High Priority Features

Processes and Events

• Memory protection (User vs Kernel mode, ring 0/3)
• Process management (fork, exec, exit, wait)
• Scheduler (multiple algorithms)
• Interrupts and exceptions (IDT, ISR handlers)
• Signals (POSIX-like signal handling)
• Timers and RTC (Real-Time Clock driver)
• Wait queues (process synchronization)
• System calls (INT 0x80 interface)
• Multi-core support (SMP)
• Thread support (POSIX threads)

Memory Management

• Paging (virtual memory with page tables)
• Buddy system (physical page allocator)
• Slab allocation (object caching)
• Zone allocator (memory zones)
• Cache allocator (kmem_cache)
• Heap management (userspace heap)
• Virtual addressing (separate address spaces)
• Memory mapping (mmap/munmap)
• Swapping (disk-based virtual memory)
• Huge pages (2MB/4MB pages)
• Memory cgroups (resource limits)

File Systems

• Virtual Filesystem (VFS layer)
• Initramfs (initial RAM filesystem)
• EXT2 filesystem (second extended filesystem)
• Procfs (process information filesystem)
• Pipes (anonymous pipes for IPC)
• Named pipes (FIFOs)
• Tmpfs (RAM-based temporary filesystem)
• FAT32 support (DOS filesystem)
• EXT3/EXT4 (journaling filesystems)
• Symlinks (symbolic links)

Input/Output

• PIC drivers (Programmable Interrupt Controller)
• PS/2 drivers (keyboard/mouse)
• ATA drivers (IDE hard disk)
• RTC drivers (Real-Time Clock)
• Keyboard drivers (US/IT/DE layouts)
• Video drivers (text mode)
• VGA drivers (graphics mode)
• AHCI drivers (SATA)
• USB drivers (USB 2.0/3.0)
• Network drivers (Ethernet)
• Sound drivers (AC97/HDA)

Medium Priority Features

Inter-Process Communication (IPC)

• Semaphores (System V semaphores)
• Message queues (System V message queues)
• Shared memory (System V shared memory)
• POSIX semaphores
• POSIX message queues
• Pipes (anonymous)
• Named pipes (FIFOs)
• Unix domain sockets
• Signals (enhanced POSIX compliance)

Security

• User/group management (passwd, group, shadow)
• File permissions (Unix-style permissions)
• Process privileges (UID/GID)
• Capabilities (fine-grained privileges)
• SELinux (Security-Enhanced Linux)
• Seccomp (syscall filtering)
• ASLR (Address Space Layout Randomization)

Networking

• Network stack (TCP/IP)
• Socket API (Berkeley sockets)
• Ethernet driver
• IP protocol
• TCP protocol
• UDP protocol
• ICMP (ping)
• DNS resolution

Development Tools

• GDB support (remote debugging)
• Serial console output
• Kernel logging (pr_debug, pr_info, etc.)
• Build system (CMake)
• Kernel profiler (performance analysis)
• Memory leak detector
• Code coverage tools

Low Priority Features

Advanced Scheduling

• Round-Robin (RR)
• Priority-based
• Completely Fair Scheduler (CFS)
• Earliest Deadline First (EDF - real-time)
• Rate Monotonic (RM - real-time)
• Adaptive EDF (AEDF - real-time)
• O(1) scheduler
• CPU affinity
• cgroups (control groups)
• Nice values (priority adjustment)

Power Management

• ACPI support (Advanced Configuration and Power Interface)
• CPU frequency scaling
• Suspend/resume
• Hibernation
• Power profiles

Graphics and UI

• Framebuffer support
• VGA graphics mode
• Windowing system
• GUI framework
• Mouse cursor
• Terminal emulator (graphical)

System Services

• init system (PID 1)
• Login/authentication
• Shell (command-line interface)
• Daemon management (systemd-like)
• Cron (scheduled tasks)
• Syslog (system logging daemon)

Userspace Programs

• Core utilities (cat, ls, mkdir, rm, cp, etc.) - 40+ programs
• System tools (ps, kill, uptime, uname, etc.)
• Text editor (edit)
• Manual pages (man)
• Package manager
• Compiler toolchain (gcc, ld)
• Text processing (grep, sed, awk)
• Scripting language (sh, python)

Testing and Quality

• Test suite (50+ tests)
• CI/CD pipeline (GitHub Actions)
• Documentation (Doxygen)
• Unit tests (kernel unit tests)
• Integration tests (automated)
• Stress tests (memory, CPU, I/O)
• Fuzzing (security testing)

Miscellaneous

• Loadable kernel modules (LKM)
• Dynamic linking (shared libraries)
• Kernel configuration (Kconfig-like)
• Hot-plugging (USB, PCI)
• Virtualization support (KVM-like)
• Container support (namespaces)

Feature Status Summary

Implemented: See checked items above Planned: See unchecked items above

Prioritization Rationale

High Priority

Features essential for a functional, educational operating system:

• Core OS functionality (processes, memory, syscalls)
• Basic I/O and drivers
• File system support
• Development/debugging tools

Medium Priority

Features that enhance functionality and usability:

• Advanced IPC mechanisms
• Network stack
• Security features
• More device drivers

Low Priority

Advanced or specialized features:

• Power management
• Graphics/UI
• Advanced scheduling
• Optional system services

Roadmap

Near-term (next 6 months)

• Add named pipes (FIFOs)
• Improve VGA driver
• Basic network stack (IP/TCP)
• Thread support

Mid-term (6-12 months)

• Multi-core support (SMP)
• Advanced scheduling (CPU affinity)
• More filesystems (FAT32, tmpfs)
• USB support
• Sound drivers

Long-term (12+ months)

• Graphics subsystem
• Windowing system
• Package manager
• Compiler toolchain
• Container support

Contributing

Want to help implement a feature? See Contributing for guidelines.

Suggested starter features:

• Named pipes (medium difficulty)
• Tmpfs (medium difficulty)
• Additional keyboard layouts (easy)
• More test programs (easy)
• Documentation improvements (easy)

Feature Requests

Have an idea for a new feature? Open an issue with:

• Feature description
• Use case
• Priority justification

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